The present invention relates to new and improved constructions of tire blanks for vehicle tires of the type provided at their bead region or surface with a pre-vulcanized ply or a ply consisting of a harder rubber mixture than the rubber mixture usually employed at the bead region.
Such constructions are known to the art, as exemplified for instance in French Pat. No. 2,023,015. With these state-of-the art constructions the ply consists of a layer having increased hardness relative to the neighboring rubber layer or ply, so that the loads exerted by the wheel rim shoulder or rim flange can be absorbed much better. A drawback of the known constructions resides in the fact that during build-up of the tire, especially during bowing or dishing thereof, deformations occur at the region of the carcass assembly due to compression of both bead regions, these deformations oftentimes resulting in kinking or buckling. Furthermore, it has been found that due to the formation of cavities at the inside of the tire it is impossible to prevent the formation of fissures which again, during vulcanization, produce sealing difficulties.
Although such drawbacks do not arise with other known tire constructions wherein same possess a continuous inner plate at the inside of the tire, yet such tire constructions are extremely difficult to dish or bow.